Cubic boron nitride has hardness next to diamond and excellent heat conductivity. In addition, the cubic boron nitride has a characteristic that it has low affinity to iron. A cubic boron nitride sintered body comprising the cubic boron nitride and a binder phase of a metal(s) or ceramics has been applied to a cutting tool or a wear resistant tool, etc. As a prior art of the cubic boron nitride sintered body, there is a cubic boron nitride sintered body comprising cubic boron nitride, aluminum oxide, aluminum nitride and/or aluminum boride, titanium carbide, titanium nitride and/or titanium carbonitride, and titanium boride (for example, see Patent Document 1 or Patent Document 2.).